Fig. 4

Immunohistochemistry of nerves in an area between the rectum and levator ani muscle (posterosuperior group of the pelvic plexus branches). This area is characterized by the existence of VIP-positive nerves. The topographical relationship of the four nerves is shown in Fig. 1d. Panels a, d, g, and j display nNOS immunostaining; panels b, e, h, and k exhibit VIP immunostaining; panels c, f, i, and l exhibit TH immunostaining. One of the four nerves (panel e) does not express VIP. In a single nerve, panel d does not correspond to the site shown in panels e and f, as nNOS- (or TH-) positive nerves are restricted to the upper (or lower) side of the panel. VIP-positive fibers appear to be intermingled with nNOS-positive fibers. In panel i, TH-positive fibers are restricted to the left-hand side of the nerve. All panels were prepared at the same magnification (scale bar in panel a, 0.1 mm)